

000 

WWUS20 KWNS 232347

SEL0

SPC WW 232347

NDZ000-SDZ000-240700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 740

NWS STORM PREDICTION CENTER NORMAN OK

650 PM CDT WED JUL 23 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTH CENTRAL NORTH DAKOTA

       NORTH CENTRAL SOUTH DAKOTA



EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 650 PM

UNTIL 200 AM CDT.



HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 50

STATUTE MILES EAST AND WEST OF A LINE FROM 60 MILES NORTHWEST OF

JAMESTOWN NORTH DAKOTA TO 25 MILES SOUTH OF PIERRE SOUTH DAKOTA.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU0).



REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE

FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH

AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR

THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS

AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY

DO PRODUCE TORNADOES.



OTHER WATCH INFORMATION...CONTINUE...WW 735...WW 736...WW

737...WW 738...WW 739...



DISCUSSION...ROBUST SUPERCELL STORM DEVELOPMENT HAS OCCURRED AHEAD

OF WIND SHIFT/DRYLINE MOVING ACROSS WRN/CNTRL DAKOTAS THIS EVENING.

AIR MASS AHEAD OF THE WIND SHIFT WAS MODERATELY UNSTABLE AND SHOULD

CONTINUE TO FUEL INTENSE UPDRAFTS WITHIN STRONG WLY SHEAR. NARROW

CORRIDOR OF BACKED LOW LEVEL FLOW WAS ALSO SUPPORTING RECENT STRONG

LOW LEVEL ROTATION WITH A FEW OF THE CELLS. GREATER POTENTIAL WILL

EXIST FOR LARGE HAIL AS CELLS CONSOLIDATE LATE THIS EVENING AND MAY

PERSIST IN THE FORM OF AND MCS AS LOW LEVEL JET MAINTAINS MASS

INFLOW ACROSS THE AREA AND WEAK HEIGHT FALLS ASSOCIATED WITH NRN

PLAINS SHORT WAVE TROUGH PRODUCE MODEST BACKGROUND/LARGE SCALE

ASCENT.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 32020.





...CARBIN

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